Currently batteries are the primary source of power for applications requiring small, compact power sources. However, batteries have numerous limitations as compared to fuel-driven power sources such as motors and generators. Compared to these alternate energy sources, batteries have relatively lower electrochemical energy density, and must either be replaced periodically or recharged, which typically is more time consuming than simply refueling a fuel-driven power source. Thus, there is a need for miniature energy sources for the delivery of electrical and/or mechanical energy that have the superior attributes of fuel-driven motors and generators, and which can also be fabricated in similar sizes and shapes to batteries. Such miniature energy sources would have distinct advantages over batteries, such as the ability to exploit the large energy densities of fuels (compared to the relatively lower electrochemical energy density of batteries), and the ability to quickly recharge or refill the energy storage medium (e.g., a fuel reservoir), thereby overcoming the relatively long times required to recharge a battery system.
As known in the art, microfabrication processes are utilized to construct miniature devices that can be batch fabricated at a relatively low cost. In this regard, multiple devices are typically manufactured on a single wafer during microfabrication. Well known microfabrication techniques are used to form similar components of the multiple devices during the same manufacturing steps. Once the multiple devices have been formed, they can be separated into individual devices. Examples of microfabrication techniques that allow the batch fabrication of multiple devices include, but are not limited to, sputtering, evaporation, etching, electroforming (e.g., electroplating, electrowinning, electrodeposition, etc.), packaging techniques (e.g., lamination, screen printing, etc.), photolithography, and thick or thin film fabrication techniques. Since a large number of devices can be formed by the same microfabrication steps, the cost of producing a large number of devices through microfabrication techniques is less than the cost of serially producing the devices through other conventional techniques. It is therefore desirable, in many applications, to fabricate devices through microfabrication techniques.
Recent advances in microfabrication technologies have enabled the realization of miniature power sources for the conversion of fuel energy to electrical and/or mechanical energy. It is the purpose of this invention to apply such microfabrication technologies to the realization of compact power sources.